City officials are firing up their emergency operations center and canceling days off for police.

The weekend will include the opening games of the San Francisco Giants divisional playoffs, a San Francisco 49ers game, the annual Fleet Week celebration featuring the Blue Angels and the America's Cup World Series yachting races.

Add to that mix a highly popular bluegrass festival in Golden Gate Park and street festivals in North Beach and elsewhere and it has the makings for jam-packed streets and transit challenges.